SALEM — Oregon is erecting a 250-bed temporary hospital in Salem so as to free up other hospital beds around the state for coronavirus patients.

The Oregon Medical Station is a mobile emergency hospital that the state purchased several years ago in case of a health crisis. Gov. Kate Brown said the facility, which is being set up at the Oregon State Fairgrounds, should be operational by Friday.

The state’s overriding goal is to slow the progression of COVID-19, so as not to overwhelm Oregon’s health care system. Brown and other state officials said that is why restaurants, bars, schools and all large events have been closed.

“All the things we’ve been trying to do, as grievously hard as they are for the economy, are single-mindedly aimed at the notion of making sure we don’t run out of hospital capacity,” Pat Allen, the director of the Oregon Health Authority, told the Legislature’s Joint Special Committee on Coronavirus Response on Wednesday.

Along with setting up the temporary hospital in Salem, officials want existing hospitals to create 1,000 temporary beds statewide. Officials also are exploring whether hotel, college dorm rooms or other places could be used.

“Are there facilities we can literally stand up in parking lots?” Allen said.

These would be “stepdown” facilities, requiring fewer traditional medical staff. Allen said they could serve patients who normally would be released from hospitals into nursing homes and other care facilities, which now have been closed to the public; less-sick patients who otherwise would be sent to regular hospitals; and homeless individuals and others who no longer require hospitalization but cannot continue their recovery at home.

“The idea is to basically within the next three to four weeks stand up as much of that kind of collection of care as we possibly can,” Allen said.

Current statistics suggest about 20% of COVID-19 cases require significant medical intervention, though including 5% to 8% who must be cared for in ICUs, he said.

The number of cases is accelerating. As of Wednesday morning, 75 cases had been reported so far this year, up from 39 on Sunday. Forty-seven of those 75 cases were in people age 55 or older. Nineteen were among people aged 35-54.

Cases have been identified in 14 of Oregon’s 36 counties, but the number will grow as testing expands.

Multnomah and Linn counties operated drive-thru testing centers in response to localized outbreaks, but Allen said that is impractical on a statewide basis due to the lack of medical personnel and supplies. However, the state is contracting with private labs to run tests in addition to the state medical lab. Some health providers are testing patients as needed.

Allen explained that disease outbreaks follow a bell curve. Cases unfold slowly at first and then spike up before declining, which is why Oregon officials talk “flattening the curve” — reducing the overall spike in cases. The goal is to decrease the impact on the health care system at any one time, although it could extend the overall length of the outbreak.

Without such action, Allen said, the exponentially increasing cases of severe COVID-19 will quickly exceed the capacity of overall hospital beds in Oregon, beds in intensive care unit, ventilators and skilled medical staff.

If that happens, Allen told legislators, hard decisions will have to be made about who gets care and who doesn’t.